A blog by Catharine Ellis

Where is YOUR Indigo Grown?

I first met Sarah Bellos of Stony Creek Colors in 2016 when she spoke at the Growing Color Symposium at the NC Arboretum in Asheville. She presented her vision for growing and extracting indigo in Tennessee. Her goal was to introduce natural indigo to the denim industry, which is currently a huge consumer of synthetic indigo (a serious source of environmental pollution). She was partnering with Tennessee farmers who had previously grown tobacco and planned to process indigo dye locally.

Air drying of traditional burley tobacco in TNSome Tennessee grown tobacco is cured by smoking with wood fire

I must admit that I was somewhat skeptical. The project seemed too big and too optimistic. I didn’t know anyone who had successfully grown indigo dye plants on the scale that she described.Most dye plants are grown for commercial purposes in India or South America, where the price of labor is far less. Indigo was grown in the Southeast coastal regions of South Carolina and Georgia in the 17th and 18th centuries but, to my knowledge, has not been grown commercially in North America since that time.

On a recent visit to Stony Creek near Nashville, TN I was very pleasantly surprised and now believe that they are truly on the way to something successful and very much needed. I’d like to tell you why I believe this.

The first place visited was the “test farm”.I had envisioned a small plot of Persicaria tinctoria but was amazed to find that the test farm was a densely planted, multiple acre farm tract where several strains of Persicaria tinctoria are growing next to the tropical varieties of indigo(Indigofera suffruticosa and Indigofera tinctoria).

Tropical indigo plants (Indigofera suffruticosa), harvested and continuing to grow in foreground, not yet harvested in backgroundSarah in the test field, where several varieties of indigo are grownPersicaria tinctoria, in bloom

Why grow so many different types of plants? Sarah and her staff are constantly asking questions and testing: Which varieties can be sown directly in the ground? Which need to be started in the greenhouse? Some strains bloom more readily than others (great for seed production but not so good for indigo production). Which plants can be dried for future extraction? What is the indigotin content vs. the biomass of the plants? Which can be harvested most efficiently?

I believe that the Stony Creek team is concluding that there is wisdom in growing more than one variety of indigo.The farmers are currently growing many acres of indigo for pigment extraction. All farms are within a reasonable drive to the factory, as it is necessary to process the indigo leaves quickly.

The next stop was Stony Creek’s lab.Walking in the door I saw that the dye chemist, Summer Arrowood, was pulling leaves from Persicaria tinctoria stems that had been harvested earlier that morning. She was weighing those leaves and recording the leaf-to-stem ratio. Next, individual bags of leaves (from very specific plants in very carefully identified locations at the test farm) were processed to extract the indigo pigment. I sensed that this was part of each day’s work at the lab. The leaves were soaked in hot water, the liquid was pumped into vessels for aeration, the paste was allowed to settle and then filtered. Several hours later, each batch of leaves had produced a small amount of indigo pigment. These were tested, labelled and stored for future reference. They report that their indigo contains 25-35% indigotin which is a very concentrated output.

Vessels for test extractions of pigment. Sarah is holding the piping used for introducing oxygen into the indigo extraction in order to precipitate the pigment.Filtering of test pigmentPigment extracted from test extractionsEach sample batch of pigment is carefully labeled for reference

Stony Creek is experimenting with extraction from dried plant material in order to extend the production season.

The production factory is located in a county-owned, former tobacco factory and leased by Stony Creek.Here, 20,000 pounds of indigo plant material can be processed in a single batch. The factory is set up with modern equipment, carefully laid out, and efficient. Stony Creek precipitates indigo pigment without the use of lime (calcium hydroxide). When too much lime is used during the process, it will remain in the indigo pigment and skew the weight of anyavailable indigotin. The extraction without lime is one of the reasons the pigment has such high levels of indigotin. The pigment paste is carefully filtered using processes that Stony Creek has developed specifically for indigo.

Truck trailers used for indigo harvest and initial steeping of plants.Water that has been collected from the root and heated in solar tanks is used for extracting the indigo.Stainless tanks are used for aerating the indigo. Stony Creek has recently installed two additional tanks.Plastic tanks are used for settling of the indigo paste.All indigo paste settles to the very bottom of the tanks. The remainder is waste water, that is properly neutralized before discarding.

How has Stony Creek come this far so quickly? Sarah Bellos has an academic background and experience in natural resources management and sustainable agriculture. She is a self-taught natural dyer; she and her sisters operated a dye business for several years under the name Artisan Natural Dyeworks. Stony Creek employs skilled and smart people, who know chemistry, plants, agriculture, and manufacturing. The farmers, who grow the indigo, are benefiting from a cash crop that has the potential to replace the tobacco that grew here for so long. Stony Creek is currently selling indigo paste to denim producers and they are able to test/replicate the warp dyeing process used by the denim industry in their lab. Sarah had a vision to produce natural indigo and they are making it a reality.

This chart says it all!

At a time when some of us are unsure if we are purchasing natural indigo or synthetic indigo (or a mix of both) Stony Creek is a beacon of light. I have used their indigo and it is excellent. Of course I will purchase my indigo from them! I will encourage other dyers to do the same.

Stony Creek is NOT yet set up for visitors. Right now, they need to focus on the work at hand and continue to develop their current products: indigo, black walnut paste extract (that really works!), and a madder extract paste (currently from Rubia tinctorium roots grown in India until their own roots are ready for harvest).

After this year’s indigo harvest they plan to move the lab to the factory location and at some time in the future will be able to offer workshops onsite. I hope that you will consider helping to grow this promising endeavor by trying out their excellent indigo, and other extracts available for order online at their website. Other dye suppliers are also beginning to carry and sell Stony Creek Indigo.

The day we visited the factory, there was no indigo being processed. It had rained the day before and the indigo plants cannot be harvested when wet; this whole process is tied closely to the land. Before we left in the afternoon, the truck and trailer had left for the fields, ready to be loaded with indigo plants early the next morning.

12 thoughts on “Where is YOUR Indigo Grown?”

Isn’t this amazing? I’m in awe of their undertaking—the vision and energy required to manifest that dream. Hats off to these hardworking, innovative, brave and visionary people! Yes, I’ll definitely order indigo from them.

Catharine, Thank you for sharing this information. I continue to grow my little patch of indigofera suffruiticosa every year, so I knew that it could be grown successfully in the region. I had no idea that such a big operation was happening. Exciting!

I experimented growing indigofera tinctoria and suffruticosa, but I have little sun and very poor soil. The tinctoria I grew in pots. The suffruticosa I started in pots, then transplanted in the ground. Neither made it to reseeding. I will leave growing to the professionals and buy mine from Stoney Creek.

I love this story of hope and success. . Some people really are dedicated to succeed where most people think it is impossible to achieve success. This project sounds serious and wish for them a long life of growing blue and other nice pigments. I grow some Japanese indigo and would love to participate in some of their future workshops. I keep Stoney Creek in my mind for future purchase.

What a timely post. I just purchased some indigo pigment from Stony Creek and wrote a little blurb about the thought process behind this purchase on Instagram. Thank you for sharing these images as well as your experience.